Circuit breaker



CIRCUIT BREAKER Filed Sept. 26, 1956 E. O. SCHWEITZER, JR

Newf 29, 1938.

Patented Nov. 29, 1.938

UNITED "STAT-ES -ePArfrsvlsi'r OFFICE Claims.

My invention relates, generally, to 'circuit breakers and ithas particular relation to circuit breakers for use inV connection-with high voltage power circuits. This application constitutes a continuation, in part,.of my copending applica# tion, Serial No. 64,800, led February 20, 1936.

In my copending application I have disclosed means for effecting thenal break in an electric circuit between two portions ,of a non-metallic conducting liquid for the purpose of reducing the possibility of the formationof an arc which is ordinarily formed when an-electric circuit carrying current is opened. For this purpose I have provided a pair of separablecontact members, one oi which is immersed in a suitable nonmetallic liquid, such as a dilute` solution of sulphuric acid, hydrochloric acid, zinc sulphate, and the like, while the ,other contact ,member is mounted for movement into and out of the liquid. Surrounding the lower end ofthe movable contact member is a cup formed of insulating material that is arranged to .always maintain aportion of the liquid in engagement therewith. When the movable contactV member carrying .the insulating cup at its lower end is removed vfrom the liquid, the circuit between the vcontact members is broken between twoportions Yof .thejconducting liquid, rather than between the conducting liquid and one of the `contact members. When this type of circuit opening is employed there is little, if any, tendency -for an arc Vto be formed for the reason that the thermionic emission, which is ,present-when a circuitis broken between metallic contact members or betweena metallic contact member andaconducting liquid, is absent. Moreover,l since lthe.speciclieat of the conducting liquid is relatively high ,as compared to that of a metal, such as copper, the rise in temperature of the non-metallic lconducting liquid will be relatively small as compared to the temperature rise of metallic contact members when a circuit is opened thereby.

The object of the present invention, generally stated, is to apply the foregoing principles of operation to a commercial form of vcircuit breaker which shall be simple and eicientin operation,l

and which may be readily andeconomically manufactured and installed.

An important object of my invention is to provide for opening a high `voltage electric circuit between two portions of a non-metallic conducting liquid.

Another important object of my invention is to provide for opening Va high voltageelectric circuit between twoportions oi anon-metallic conducting uid at a plurality ofindividual points 4 in the circuit.

Y A further Vobject of my invention is to provide a circuit breaker having two separate conducting circuits, onethrough a non-metallic conducting liquid and `the other through a metallic shunt member, together with operating means for i'lrst openingthe circuit through the shunt member and then the remaining circuit between two portions of the conducting liquid.

' Still another object of my invention is to provide for opening an electric circuit between two portions of ,a non-metallic conductingliquid in each ofa pair of seriesfconnected chambers.

Otherobj'ects of my'invention will, in part, be Obvious and in part appear hereinafter.

My invention, accordingly, is disclosed in the embodiment hereof shown in the accompanying drawing, andit comprises the features of construction, `combination of elements, and arrangement of Darts which .will be exempliedin the construction hereinafter set forth, and the scope of the application `of which will be indicated in the appended claims.

'For a more complete understanding of -the nature andsoope ofrny" invention, reference may be had to the following detailed description, taken in connection with the accompanyingrdrawing, in which:

1Figure'1 vis a View, partly in side elevation and partly in section, showing aconcrete embodiment of my invention;

,Figure'Z is` an enlarged view, in top plan, showing the construction of the insulating cup at the lower end of each of the movable contact members in detail; and

Figure 3 is a sectional view taken along the line 3-3`of1igure 2. l

,Accordingto' the present invention, I have provided for Vembodying'the principles of operation of the circuit breakeridisclosed in my copending application, hereinbeiore referred to, vin one form. of a. commercial jtype of circuit breaker which is employed in connection with high voltage power circuits. 'This particular form Yof circuit breakenin'its commercial embodiment as now available in the open market, includes a pair of xedyjcontact members, which are suitably insulated, and which are arranged for connection into an electric circuit. Each of the contact membersV is provided with an arcing chamber which is partly filled with a. suitable non-conducting liquid, such `as Aa halogenated hydrocarbon. A kconnecting member comprisinga pair of contact rods connected'I by a suitable yoke is Vprovided and connected to a suitable operating mechanism. The contact rods are arranged to move in the arcing chambers through the insulating liquid and into contact engagement with the fixed contact members. When the connecting member is moved upwardly, the circuitI is broken in each arcing chamber when the contact rod therein leaves its individual fixed contact member. The arc which is formed when the circuit is broken when carrying current is extinguished by means of the insulating liquid. If the circuit is carrying a large current, correspondingly severe arcing conditions may arise which require special precautions to be taken in order to avoid damage to the circuit breaker itself and possible damage to surrounding equipment. Y Y

By applying the principle of opening a circuitv between two portions of a non-metallic conducting liquid to a circuit breaker of this type, I have been able-to open circuits carrying very heavy currents with susbtantially no arcing'. I substitute a non-.metallic conducting liquid for the insulating liquid in the arcing chambers and` provide each of the contact rods or, in this case, electrodes, at its lower end, with a cup formed of insulating material which is arranged to always maintain a portion of the `conducting liquid in engagement with the electrode. When the electrodes are moved upwardly to open the circuit, the final break occurs between two portions of the conducting liquid, rather than between two metallic contact members, as was formerly the case.

Referring now particularly to Figure l of the drawing, it will be observed that the reference characterv I0 designates, generally, a commercial form of circuit breaker to which my invention has been applied for the purpose of increasing its rupturing capacity and providing substantially arcless operation. As illustrated, the circuit breaker I0 comprises a housing II having insulators I2 and I3 extending through the bottom wall thereof for insulating conductors I4 and I5 therefrom. The conductors I4 and I5 may be connected to an electric circuit in a manner well known to those skilled in the art. The conductors I4 andv I5 are provided `at their upper ends with terminal members or electrodes I6 and I1 which have liquid pots or chambers I8 and I9 l connected thereto and forming extensions thereof in an upward direction. The chambers I8 and I9 are composed preferably of a conducting material, such as copper, and they form the arcing chambers of a commercial form of circuit breaker. The interior constructionrof the chambers I8 and I9 may be identical, chamber I8 being illustratedin section by way of example. As shown, the chamber I8 is provided with a lining 24 of Y insulating material, such as i'lber, having an apertured cap 25 at the upper end thereof. A bath 26 of a suitable non-metallic conducting liquid is poured into the chamber I8 to the level indicated at 21. As set forth hereinbefore, this liquid may compriseI a dilute solution of sulphuric acid, hydrochloric acid, zinc sulphate, or the like. A common salt solution may also be employed.

Each of the chambers I8 and I9 is provided with a movable electrode, 28 and 29, respectively, which are slidably mounted. in suitable insulators 30 and 3l that are mounted at the upper ends of thechambers I8 and I9, as illustrated. The electrodes 28 and 29 are mechanically and electrically interconnected by a yoke 32 which is carriedy by an operating rod 33 that forms a part of an operating mechanism designated generally by the reference character 34. The operatingmechanism 34 maybe of any suitable type which is arranged to move the operating rod 33 upwardly a sucient distance to open the circuit in the desired manner. Since any suitable operating mechanism, well known to those skilled in the art, may be employed, a detailed description thereof is not set forth herein.

In order to provide a shunt path between the conductors I4 and I5 so that the liquid 26 will not be required to conduct line currents under normal operating conditions, a shunting member 35 is provided which may be carried by and therefore operated in conjunction with the yoke 32. The shunting member 35 may comprise a plurality of laminations of copper to provide the required conducting characteristics. The ends of the shunting member 35 are arranged to engage contact blocks 36 and 31 that are carried by the chambers I8 and I9. It will be recalled that the chambers I8 and I9 are formed of conducting material and, therefore, when the shunting member 35 is in engagement with the contact blocks 36 yand 31 a complete metallic circuit is provided between the conductors I4 and I5.

With a View to providing for the final break in each of the chambers I8 and I9 between two portions of the liquid 26, the lower end of each of the electrodes 28 and 29 is provided with a cup 40, the details of construction of which are illustrated more clearly in Figures 2 and 3 of the drawing. As there shown, the cup 48 is formed of insulating material, such as a phenolic condensation product. The cup 4l) is internally threaded to receive a contact plate 4I in threaded engagement therewith. The contact plate 4I is formed of conducting material such as copper and is provided with an internally threaded boss 42 for mounting on the lower threaded end of the electrodes 28 and 29.

It will be understood that the cup 40 is filled with the conducting liquid 26 which will then be in contact engagement with the contact plate 4I. With a view to insuring that the circuit will be broken between two portions of the liquid 26 a cover 43, having apertures 44 near the periphery thereof, is threaded into the upper end of the cup 40, as illustrated. Since the cover 43 is formed of a suitable insulating material and further, since a sleeve 45 of insulation is provided .around the rod 28, the only path through which the current can flow from the contact plate 4I is through the apertures 44. There is then no likelihood of an arc being formed because of the breaking of the circuit between the metallic contact plate 42 and a portion of the conducting liquid 26 or between the electrodes 2B and 29 and the conducting liquid 25.

In operation, `the normally closed position or the circuit breaker I0 and the various parts thereof is shown by the full lines in Figure l of the drawing. When it is desired to open the circuit, the operating rod 33 is moved upwardly by the operating mechanism 34 inthe conventional manner. The shunt member 35 is first moved out of engagement with the contact blocks 36 and 31, thereby transferring the entire ow of current to the conducting liquid 26 in each of the chambers I8 and I9. The continued upward movement of the operating rod 33 lifts the cup 40 carried by each electrode 28 and 29 out of the conducting liquid 26. Because of the provision ofthe cups 40, it will be understood that the circuit is finally broken between two portions of the conducting liquid 26 in each of the chambers I8 and I9, thereby providingtwo breaks in series between the conductors I4 and I5. The yoke 32 and oper- 75 ating elements carried thereby is moved to the a1- ternate position shown by the broken lines. In order to close the circuit, the foregoing described sequence of operation is reversed and the operating rod 33 is moved downwardly. as will be readily understood.

Since certain changes may be made in the above construction and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

l. An electric switch comprising, in combination, two iixed electrodes, a separate enclosure for each of said electrodes, two mechanically and electrically connected movable electrodes adapted to be moved toward and away from said fixed electrodes in said enclosures, a non-metallic conducting liquid in each of said enclosures for completing a circuit between said electrodes in said enclosures, and means for breaking said circuit in each enclosure between two portions of said liquid therein to provide an air gap between the electrodes in each enclosure.

2. An electric switch comprising, in combination, two fixed electrodes, a separate enclosure for each of said electrodes, two mechanically and electrically connected movable electrodes adapted to be moved toward and away from said fixed electrodes in said enclosures, a non-metallic conducting liquid in each of said enclosures for completing a circuit between said electrodes in said enclosures, shunt circuit means also completing a circuit between said fixed electrodes through said liquid, and means for sequentially opening said circuits including means for first opening the circuit completed by said shunt circuit means and means for opening the remaining circuit between two portions of said liquid in each enclosure to provide an air gap between the electrodes in each enclosure.

3. An electrical circuit breaking -device comprising, in combination, a pair of xed electrodes mounted in insulated spaced relation, a chamber composed of conducting material individual to each electrode, a body of non-metallic conducting liquid in each chamber, an electrode mounted for relative movement with respect to said liquid 'in each chamber, means interconnecting said movable electrodes to complete a circuit between sai-d fixed electrodes through said liquid, shunt means engaging said chambers for also completing a circuit between said fixed electrodes, and means for sequentially opening said circuits including means. for rst opening the circuit cornpleted by said shunt circuit means, and means carried by each movable electrode for opening the remaining circuit between two portions of said liquid in each chamber to provide an air gap between the electrodes in each chamber.

4. Ari electrical circuit breaking device comprising, in combination, a pair of fixed electrodes mounted in insulated spaced relation, a chamber individual to each electrode, a body oi non-metallic conducting liquid in each chamber, an electrode mounted for relative movement with respect to said liquid in each chamber, means interconnecting said movable electrodes to complete a circuit between said iixed electrodes through said liquid, and a cup composed of insulating material mounted at the lower end of each movable electrode for maintaining a portion of said conducting liquid in engagement therewith whereby said circuit is opened between two portions of said liquid in each chamber when the movable electrodes are moved to the circuit opening position to provide an air gapv between the electrodes in each chamber.

5. The combination, with a contact member of an electrical circuit breaking device movable relative to a bath of non-metallic liquid, of a contact plate fastened to the lower end of said contact member, a cup formed of insulating material and carried by said plate and disposed to maintain the liquid in contact therewith, and an apertured cover formed of insulating material covering said cup.

EDMUND O. SCHWEITZER, JR. 

